1. Field of the Invention
This disclosure relates to a cleaning solution and a method of cleaning a semiconductor device using the same, and more particularly to a cleaning solution for completely removing various polymers attached to a tungsten wiring of a semiconductor device and a method of cleaning a semiconductor device using the same.
2. Description of the Related Art
Recently, semiconductor devices have been greatly improved as information processing apparatus such as a computers are rapidly developed. The semiconductor device is required to have rapid response speed and large storage capacity so that a semiconductor manufacturing process is developed to improve integration density and reliability of the semiconductor device.
To accomplish high integration density of a semiconductor device, a cell of the semiconductor device should be reduced. In accordance with reduction of the size of the cell, all the patterns formed on a substrate have reduced dimensions and processing margins are also decreased. Hence, the semiconductor device may not have adequate electrical insulation and refresh characteristics. Also, sizes of the patterns are greatly reduced and multi-layered wirings are demanded according as the semiconductor device has high integration density.
As design rules for semiconductor devices are reduced, a metal having a relative low electrical resistance is used for metal wirings of the semiconductor device instead of a metal having high electrical resistance. For example, tungsten silicide, rather than tungsten, is employed for the metal wiring of the semiconductor device to be used as a gate electrode or a bit line of a volatile or non-volatile memory device.
As processes of forming a metal wiring and a contact hole for multi-layered metal wirings are more frequently employed in a semiconductor manufacturing process, a dry etch process for etching a metal and an ashing process for removing a photoresist pattern are also frequently performed. When the metal wiring is formed using the dry etch and ashing processes, impurities are generated from a dry etch gas, the photoresist pattern, an oxide film, and a tungsten film and the impurities are attached to a sidewall of the metal wiring. The impurities may increase electrical resistance of a semiconductor device or may cause an electrical short between adjacent metal wirings when the impurities remain on the metal wiring. Thus, these impurities should be removed from the metal wiring.
Japanese Patent Laid Open Publication No. 10-779366 discloses a method of removing impurities remaining on a substrate using a cleaning solution including about 24 percent by weight of sulfuric acid, about 5 percent by weight of aqueous hydrogen peroxide solution, about 0.02 percent by weight of hydrogen fluoride, about 0.075 percent by weight of N-dodecyl benzene sulfonic acid and water. The impurities on the substrate are removed by immersing the substrate into the cleaning solution for about 10 minutes and rinsing the substrate using deionized water for about 7 minutes.
Korean Patent Laid Open Publication No. 2000-61342 discloses a method of removing polymers remaining on a substrate by successively using a cleaning solution of sulfuric acid (H2SO4) and aqueous hydrogen peroxide solution (H2O2), a cleaning solution of hydrofluoric acid (HF) and water (H2O), and an SCl cleaning solution. The polymers are generated after a dry etch process for forming a tungsten suicide wiring on the substrate.
Meanwhile, an organic stripper including hydroxylamine is generally used in a cleaning process for removing impurities generated after a process of etching a tungsten wiring because the organic stripper may not cause damages of the tungsten wiring and an underlying film. However, the organic stripper may not completely remove the impurities remaining on a substrate. The organic stripper may not effectively remove oxygen-containing polymers (polymeric oxides) generated during etching of the tungsten wiring so that the impurities are not completely removed from the substrate. Additionally, because the impurities attached to the tungsten wiring are adequately removed from the tungsten wiring for more than about 20 minutes, the time required for removing the impurities may be too long when the impurities are removed using the organic stripper.
To solve the above-mentioned problems, an improved organic stripper has been developed. The improved organic stripper additionally includes fluorine-containing chemicals like HF or NHF4, an organic solvent, and a corrosion inhibitor. The organic solvent can prevent a metal wiring from being damaged due to the fluorine-containing chemicals. However, the improved organic stripper may not effectively remove polymers generated during etching the metal wiring and the improved organic stripper is very expensive. Also, the improved organic stripper may excessively etch some underlying films to such an extent that the improved organic stripper can hardly be employed for a semiconductor manufacturing process.
Embodiments of the invention address these and other disadvantages of the conventional art.